This deserves more time than I can give it right now, but in nutshell form;
Many look at the differences between the ways God dealt with people in the Old and New Testaments and come away with a dilemma; how do we reconcile the idea of an unchangeable God with the obvious difference between "Wipe out this heathen city completely, leave nothing alive" and "Love your enemies. Bless those who curse you." ?
This led some to postulate a Demiurge, or to speculate that the OT writers were attributing to God the desires of mere men, or even to entertain the idea that God "evolves". It has, of course, given some a convenient excuse to write off the existence of God altogether, or at least to be mad at Him (or often both).
But another angle has occurred to me that I haven't heard discussed before, and that is the idea that God treats us differently - not because He has changed - but because WE have.
An analogy may help. When my son was a toddler, he got into a lot of things he shouldn't have and he also (like many two-years-olds) often experimented with the boundary between submission and defiance. For his own safety, and to establish certain truths more firmly in his mind, I would sometimes swat his behind or - later - thump him in the head (I found this much handier after I began to have back problems).
He is now seventeen. What kind of pathetic spactacle would it be if I still chased him around the house or down the grocery aisle swatting his behind? What would it say about me if I continued to thump him in the head?
The way I deal with him has changed a great deal over the years, not because I have changed, but because he has changed.
So the question in my mind is, have we - mankind - changed? Is this why God seems to treat us differently now? And is it partly because He has treated us differently (by revealing His perfect will through His Son) that we have changed? Before a certain time in history, was "eye for eye, and tooth for tooth" the only truly appropriate way of handling unregenerate man?
I'd be interested to know if any of the Mass'keteers think this might tie in with Mimetic Theory, if it holds water at all.